Audible signalling means for clothes dryer lint traps



Jan. 29, 1957 R. DUNKELMAN 2,779,305

AUDIBLE SIGNALLING MEANS FOR CLOTHES DRYER LINT TRAPS Filed Oct. 5, 1955INVENTOR.

ROBERT L. DUNKELMAN HIS ATTORNEY AUDIBLE SIGNALLHIG MEANS FOR CLOTHESDRYER LINT TRAPS Robert L. Dunkclman, Louisville, Ky., assignor toGeneral Electric Company, a corporation of New York Application October5, 1955, Serial No. 538,590 2 Claims. (Cl. 116112) My invention relatesto clothes drying machines of the type in which heated air is circulatedthrough the clothes container and more particularly to such machinesincluding lint separators for removing lint from the air stream leavingthe clothes container.

Lint separators or traps are customarily included in domestic clothesdrying machines so that quantities of lint will not be blown into thesurrounding room during the drying operation. However, after a machinehas been used for a greater or lesser period of time, the separator ortrap usually becomes so clogged with lint as to interfere with theproper operation of the machine. The clogging of the separator restrictsthe air flow therethrough and thus interferes with the air circulationthroughout the entire machine. As a result the machine can not operateto dry clothes with its normal efiiciency.

The lint separators or traps are therefore ordinarily constructed thatthey may be cleaned out by the operator. For example, they are sometimesconstructed in the form of a removable drawer. A problem is createdthough in that the operator is ordinarily not immediately aware of itwhen the separator becomes so clogged as to need cleaning. The operatormay very well run the machine for another time after the separator isclogged before she realizes it, resulting in a load of improperly driedclothes.

To obviate this difficulty means have been provided heretofore forautomatically notifying the operator of the clogging of the lintseparator. For example, an electric buzzer has been used for thatpurpose. These means have, however, all been relatively expensive toproduce and assemble Within the machine, and for that reason have notenjoyed widespread use.

Accordingly, it is a primary object of my invention to provide a new andimproved, but yet inexpensive arrangement for use in a clothes dryer forproducing an audible signal upon the clogging of the clothes dryer linttrap.

Another object of my invention is to provide audible signalling meansfor indicating the clogging of a clothes dryer lint trap, whichsignalling means are operated by the flow of air therethrough and areresponsive to air pressures created within the dryer by the clogging ofthe lint trap.

In carrying out my invention I provide a clothes dryer having a clothescontainer and means for circulating a stream of heated air through thecontainer. A lint trap is suitably mounted for removing lint from theair leaving the container; and by my invention an audible whistle meansis provided for indicating a clogged condition of the lint trap. Thiswhistle means is of the type which is operated by the flow of airtherethrough, and it is arranged so that it is responsive to thepressure conditions within the dryer. The whistle means is normallyinactive when the lint trap is not clogged, but it produces an audiblesignal in response to the changed pressure conditions created within thedryer when the trap does become clogged with lint. Thus a signal isautomatically produced to warn the operator that the trap should beemptied.

2,779,305 Patented Jan. 29, 1957 The features of my invention which Ibelieve to be novel are pointed out with particularity in the appendedclaims. My invention itself, however, both to its organization andmethod of operation, may be best understood by reference to thefollowing description taken in conjunction with the accompanyingdrawings in which:

Fig. l is a perspective view of a clothes dryer including audiblesignalling means embodying my invention in one form thereof, the viewbeing partially broken away and partially in section to illustratedetails of construction;

Fig. 2 is a perspective View of the lint trap included in the dryer ofFig. 1;

Fig. 3 is a fragmentary sectional view taken on the line 33 of Fig. 1;

Fig. 4 is a fragmentary front elevational view of a clothes dryerincluding another embodiment of my audible signalling means; and- Pig. 5is a fragmentary sectional view taken on the line 5-5 of Fig. 4.

Referring now to Fig. l, l have shown therein a clothes dryer 1iincorporating one embodiment of my improved audible signalling means.The dryer includes a rotatable drum or basket 2 which is mounted forrotation about a generally horizontal axis. The basket 2 is disposedwithin an outer enclosing cabinet structure 3, and aligned open ings and5 are provided respectively in the front walls of the basket and thecabinet structure for the loading and unloading of clothes from thebasket. The openings 4 and 5 are flanged as shown to prevent clothesfrom dropping down between the basket and the cabinet. A door 6 hingedlymounted on the cabinet closes the opening 5 during operation of themachine.

For rotating the basket 2 during the operation of the dryer there isprovided an electric motor 7 which is connectedto the basket by asuitable belt drive 3. The

pulleys (not shown) mounting the belt are so arranged that the basket 2is driven at a suitable speed for tumbling articles of clothing placedtherein. The basket 2 preferably includes upstanding ribs on the innersurface thereof to aid in producing the tumbling action. Besides thebasket 2, the motor 7 also serves to. drive air moving means forcirculating a stream of air through the basket during the operation ofthe machine. The air moving means comprises a centrifugal blower {5'which is driven from the motor 7 by means of a direct coupling Ill. Theblower 9 draws in air from the surrounding room through a conduit llwhich leads from a screened air inlet opening 12in the toeboard 13 ofthe cabinet.

The air drawn in by the blower is discharged through an opening 14 atthe top thereof into a space 15 which is separated from the rotatingbasket by a bafile 16. As shown, the baffle 16 extends upwardly from thebase of the machine to a point in the general vicinity of an electricalheating element 17 mounted at the top of the machine, the bafiie inbeing curved arcuately around the perforated side wall it of the basketfor a portion of its length. The air discharged from the blower 9 flowsupwardly through the space 15 and passes outwardly therefrom across theelectrical heating element 17. The heated air still under pressure fromthe blower then flows downwardly through the foraminated cylindricalwall 18 of the rotating basket. The heated air moves through the basketand the articles of clothes being tumbled therein, extracting moisturefrom the clothes during its passage, and next passes into a collectingchamber 39 lying beneath the basket 2 on the opposite side of the bafile16 from the space 15. From the chamber 19 the air is discharged out ofthe cabinet into the surrounding room through an appropriate lint trapstructure 2i mounted in the toeboard 13.

The heated air in moving through the basket 2, of course, picks upappreciable lint from the clothes being greases tumbled, and the purposeof the lint trap or separator is to remove substantially all of thislint from the exhaust air before it leaves the dryer. Although myinvention is not limited to any particular form of lint trap orseparator, one suitable trap is shown in Fig. 2 by way of example. Thistrap comprises a removable drawer 21 which slides into and out of thetoeboard 1.3. The drawer is open across its top for the entry of air,but includes a slanted screen 22 through which the air must flow inleaving the machine. The screen 22 filters the lint from the air so thatit collects in the drawer 23., and when sufiicient lint has beencollected, the drawer may be slid out of the machine and emptied by theoperator. Preferably and as shown in Pig. 1 the front of the lint trapthrough which the air passes from the slanted screen 22 is provided witha second screen 23, both for decoration and for removing still more lintfrom the air. The air flows from the screen 22 to the screen 23 througha closed passageway formed by the sides of the drawer 231 and aremovable cover or top plate 24 (see Fig. 2). A suitable handle 25mounted on the front of the trap provides for the removal of the trapfrom the machine.

As the dryer It operates there is a continuous build-up or collection oflint within the trap 29. After the machine has operated for a greater orlesser period of time depending upon the type of clothes being dried,sufficient lint collects within the trap to clog the screen 21. Theclogging of the screen 21 restricts the air flow therethrough and thusinterferes with the proper air circulation throughout the entiremachine. As a result the machine can not operate properly so that it isineffective to dry clothes in the normal expected period of time. It is,therefore, desirable that the lint trap be removed and emptied so as toreturn the machine to its proper operation.

In order to notify the operator of the clogged condition of the linttrap, new and improved audible signalling means are provided in themachine 1. This audible signalling means according to my inventioncomprises whistle means which are normally ineifective to produce asignal or a'whistling noise but are rendered eifective to produce such anoise by reason of the clogging of the lint trap. In Fig. 3 there isshown one embodiment of this whistle means. In this embodiment a whistle26 is mounted so that its intake is from the chamber 19 within the dryerand its exhaust is to. the room outside the dryer. In other words theinlet to the whistle is on the upstream side of the lint trap 20 and itsdischarge is on the downstream side of the lint trap.

The whistle 26 is supplied with air from the exhaust air r collectingchamber 19 by means of a tube 27 which is rigidly formed in the shapeshown (Fig. 3). The tube 27 protrudes through the'toeboard 13 of themachine 1 and it mounts thewhistle 26 at its outer end. The tube itselfis mounted by means of a suitable bracket 28 fixedly attached to thedryer casing. The inner or intake end of the tube 27 is normally closedby a nipple or boss 29 formed on a resilient diaphragm 30. The diaphragm30 is secured around an aperture 31 in the toeboard 13 so that one sideof the diaphragm is exposed to the room air pressure and the other sideof the diaphragm is exposed to the pressure within the chamber 19. Thediaphragm is resilient and during the normal operation of the dryer whenthe lint trap 20 is not clogged, the diaphragm assumes the shape shownwherein the nipple 29 closes off the inlet to the tube 27. Thus no airflows through the tube 27 and the whistle 26 and no signal is produced.

However, as the lint trap clogs up so as to interfere with the exhaustair flow from the dryer, a pressure builds up within the collectingchamber 19. As the lint trap continues to clog, this pressure continuesto rise due to the operation of the blower until it becomes higher thanthe room air pressure, for example as much as 0.24 inches of waterhigher in one suitable dryer. The diaphragm 30 is, of course, exposed toroom air pressure on its one side through the aperture 31. and it isexposed to the pressure within the chamber 19 on its other side. Whenthe pressure within the chamber 19 becomes high enough due to theclogging of the lint trap, it causes a flexing of the diaphragm 30toward the toeboard 13. This flexing of the diaphragm in response to theincreased pressure within the chamber 19 pulls the nipple 29 out or theend of tube 27 and opens the tube to chamber 19. As a result air flowsfrom the higher pressure chamber 19 through the tube 27 and the whistle26 to the surrounding room, and an audible signal or whistling noise isproduced by the whistle in the process. This audible signal notifies thehousewife that the lint trap is clogged and should be removed from themachine and emptied.

The audible signal produced by the whistle continues until the dryer isshut off and the lint trap emptied. Then diaphragm 34) due to itsinternal resilience moves the nipple 29 back into tube 27, closing thetube. This prevents the whistle from being blown when the machine isplaced back in operation. The pressure in chamber 19 with the lint trapempty is not high enough to flex the diaphragm toward the toeboard andthe whistle remains inoperative. Thus the signal Which is automaticallyproduced when the lint trap becomes clogged is in effect automaticallyturned off by the emptying of the trap.

in Figs. 4 and 5, I have shown an alternate embodiment of my inventionas applied to a clothes dryer. For

simplicity and ease of understanding, elements in Figs. 4

is circulated through the rotating basket 2 in the same manner as in thedryer 1. The air is drawn into the machine by a blower 9 and is directedto a heating ele men-t at the top of the basket by means of a bathe 16.The air flows downwardly across the basket from the heating element,extracting moisture from the clothes being tumbled therein, and iscollected in a suitable chamber 19 on the opposite side of the bathe it?from the blower 9. From the chamber 19 the air is exhausted out of themachine through a suitable lint trap 29.

in order to indicate a clogged condition of the lint trap there isprovided whistle means embodying my in-- vention in an alternate formthereof. This whistle means comprises an orifice type whistle 40 whichis mounted in the toeboard 13 of the machine. The whistle element 49comprises a tube 41 having its intake connected to the exhaust aircollecting chamber 3.9 and having its outlet exhausting into the roomsurrounding the dryer (see Fig. 5). Intermediate the ends of the tube anorifice 42 is provided for producing a whistling noise Whenever airflows through the tube at a predetermined rate.

The tube 41 and the orifice 42 are so designed that the air flowtherethrough during the normal operation of the machine is ineifectiveto produce a signal. In other words when the lint trap is not cloggedand the pressure in chamber 19 is not appreciably higher than the roomair pressure, the Whistle means 40 does not produce a noise. However,when the lint trap 29 clogs up so that pressure builds up within thechamber 19, an increased air flow is caused through the whistle means.The higher the pressure, the higher is the air flow through the whistle.The orifice 4-2 is so designed that when this flow reaches apredetermined rate, it then creates an audible signal or whistlingnoise. This audible signal, of course, warns the operator that the linttrap should be emptied. The pressure with the chamber 19 at which thewhistle produces the signal may obviously be varied by changing thedesign of the whistle.

After the lint trap is emptied in response to the signal, the machinecan be placed back in normal opera tion. There is then no appreciablepressure differential across the lint trap and no signal is produced bythe whistle 40. Just as the signal is produced automatically when thetrap becomes clogged, the emptying of the trap automatically stops it.

From the above it will be seen that I have provided new and improved,but yet very inexpensive means for producing an audible signal to warnof the clogging of a clothes dryer lint trap. The means comprisesWhistle means which is blown by the changed pressure conditions withinthe dryer resulting from the clogging of the trap. Specifically, in bothof the illustrated embodiments the whistle means is blown by theincreased pressure across the lint trap itself. Whenever the pressure onthe up stream side of the lint trap increases to a predetermined levelabove the room air pressure on the downstream side of the trap, anaudible signal is produced. In one embodiment the signal is produced bythe opening of the whistle intake by a flexible diaphragm, and in thesecond embodiment the signal is produced through the design of acontinuously open whistle so that it is effective to produce a signalonly when the intake pressure rises to the predetermined level. Witheither embodiment a loud, clear signal is produced to warn the operatorthat the lint trap should be emptied.

In both of the above described embodiments I have shown my invention asapplied to a dryer having a pressure type air circulation system. Thatis, I have shown the invention in a dryer in which the lint trap isdownstream from the blower or other air moving means. It

will be obvious, however, that the invention can be utilized equallywell in dryers having a suction type system in which the lint trap isupstream of the blower. In a suction system, just as in a pressuresystem, the pressure conditions within the dryer change as the lint trapbecomes clogged and restricts the air flow therethrough. These changedpressure conditions may be utilized equally well in the suction systemto actuate the whistle means for notifying the operator. Thus it will beunderstood that I contemplate the use of my whistle means in both typesof dryer systems, pressure and suction.

While in accordance with the patent statutes, I have described What atpresent are considered to be the preferred embodiments of my invention,it will be obvious to those skilled in the art that various changes andmodifications may be made therein without departing from my inventionand I, therefore, aim in the appended claims to cover all such changesand modifications as fall within the true spirit and scope of theinvention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a clothes dryer, a clothes container, air heating means, airmoving means for circulating air over said heating means and throughsaid container for drying the clothes therein, a lint trap for removinglint from the air leaving said container, whistle means having itsintake connected on the upstream side of said lint trap, and a pressureresponsive, resilient diaphragm arranged to respond to the pressure onthe upstream side of said lint trap, said diaphragm normally assuming afirst position and flexing to a second position in response to thepressure on the upstream side of said lint trap rising above apredetermined level, said diaphragm shutting said intake of said whistlemeans in said first position and opening said intake when .in saidsecond position, whereby said whistle means is operated to produce asignal when said lint trap clogs sufficiently to cause the upstreampressure to reach said predetermined level.

2. In a clothes dryer, a clothes container, air heating means, airmoving means for circulating air over said heating means and throughsaid container for drying the clothes therein, a lint trap for removinglint from the air leaving said container, a whistle connected acrosssaid lint trap, and a pressure responsive diaphragm element controllingthe operation of said whistle, the opposite faces of said diaphragmelement being subjected respectively to the pressures on the upstreamand downstream sides of said lint trap, said diaphragm element normallyclosing the entrance to said Whistle and being flexed to open saidentrance when the pressure differential across said lint trap reaches apredetermined level due to the clogging of said trap.

References Cited in the file of this patent UNITED STATES PATIENTS2,704,896 Hopkins Mar. 29, 1955 2,753,831 Davies July 10, 1956

